<?php
abstract class Product
{
	private $paperNum=1;//试卷数目
	private $questionNum=10;//每个试卷题目数
	private $difficulty=0.2;//试卷难度
	private $rate=0.1;//重复率

	public function setPaperNum($paperNum)//设置参数
	{
		$this->paperNum=$paperNum;
	}

	protected function getPaperNum()
	{
		return $this->paperNum;
	}

	public function setQuestionNum($questionNum)
	{
		$this->questionNum=$questionNum;
	}

	protected function getQuestionNum()
	{
		return $this->questionNum;
	}

	public function setDifficulty($difficulty)
	{
		$this->difficulty=$difficulty;
	}

	protected function getDifficulty()
	{
		return $this->difficulty;
	}

	public function setRate($rate)
	{
		$this->rate=$rate;
	}

	protected function getRate()
	{
		return $this->rate;
	}

	public abstract function getProperties();
}